A cobporation of



A.L.BAUSMAN.

ROTARY PUMP.

APPLICATION FILED JULY 24,1911.

Patented July 8, 1919.

. INVENTOR. mzaawmm.

` A TTORNE YS.

UNITED sTATEs PATENT oEEroE.

ALONZO ALINTON BAUSMAN, 0F CHICOPEE, `MASSACHUSETTS, ASSIGNOB TO NATIONAL EQUIPMENT COMPANY, OF SPRINGFIELD, MASSACHUSETTS, A CORPORATION 0F MASSACHUSETTS. A

To all whom it may concern:

Be it known that I, ALoNzo LIN'roN BAus- MAN, a citizen of the United Statesof America, residing in the city of Chicopee, county of Hampden, and State of Massachusetts, have invented certain newy and useful Improvements in Rotary Pumps, of which the following is a specification.

This invention relates to rotary pumps for feeding material, such as chocolate and the like, and more particularly to the lubrication of pumps of the type and for the purpose described. By material such as chocolate and the like is meant a material to be pumped which material itself has some lubricating value and particularly such material as would be injured by contact with 'commonly used lubricants.

With the more recent developments in the confectionery art, it has become desirable to employ rotary pumps, such as gear pumps, for example,I in feeding the coating material, such as chocolate and the like, from a supply to the desired point. The attempted use of rotary pumps for the purpose of pumping chocolate has, however, led to difficulties and such pumps have not heretofore been generally successful. The trouble experienced, when such pumps have been used to pump material such as chocolate, and the reason why they have not been entirely successful heretofore, I believe is due to the difficulties arising from lubrication of the moving parts of the pump.

Special problems arise when pumps of the type mentioned are used for the purpose of pumping chocolate. Oil and other usual lubricating mediums are not satisfactory for the reason that when oil and the like is used for the lubrication of gear pumps, it is dilicult to prevent the oil from mixing with the pumped chocolate. The chocolate itself is a suitable lubricant, and the first conception is to utilize the chocolate as oil is customarily utilized, namely, by using it over and over again. The use of chocolate for lubrication in the manner described, however, is not satisfactory in that the choco- Specification of Letters Patent.

ROTARY PUMP.

Patented July 8, 19419.

Application led J' uly 24, 1917. Serial No. 182,420.

umped chocolate may circulate from thc high to the low pressure side of the pump, and in its circulation lubricate all the moving surfaces of the latter. This feature of the invention is characterized in that none of the chocolate is wasted in lubricating the pump for, after having performed its lubricating function, it is again carried to the high pressure -side of the pump and expelled. A further advantageous effect is obtained according to this feature of the invention in that fresh lubricant is continually supplied to the moving parts of the pump, as distinguished from using the material over and over again.

According to another feature of the invention, the pump of the character described is arranged to be heated, whereby the chocolate may be kept in Huid condition and at a temperature best calculated to accomplish its lubricating function.

Gther features of the invention will appear in the illustrative embodiment of it in the drawingsf Figure 1 is an elevational View of a rotary pump embodying the invention;

Fig. 2 is a cross sectional view taken on the line 2--2 of Fig. 1;

Fig. 3 is an end elevational view of the Pump thereof takensonthe line 1--11 of Fig. 3;

or more paths along which some of the l Fi 5 is a sectional plan view taken on the ligne 5-5 of Fig. 1; and

Fig. 6 is a detail sectional view taken on the line 6 6 of Fig. 5.

In the illustrated embodiment of the in vention, the well known gear pump has been shown as typifying one rotary pump in Which the invention may be embodied. The pump illustrated comprises a casing 10, which has an opening therethrough to receive a pair of intermeshing gears 11, and front and rear cover plates 12 and 13, respectively, suitably secured to the casing, as shown in Figs. 1 and 3, to close said opening. The gears 11 are keyed, as shown in Fig. 5 to shafts 14, the ends of which are mounted in bearing bushings 15 fixed in the cover plates 12 and 13 in any suitable manner.

The ends of shaft-s 14 do not extend entirely through the cover plates except for one end of one shaft 14 which extends outwardly through a suitable stung box 5) in cover 12 for driving connections with a suitable source of power. 4The ends of shafts 14, with the exception noted, and the ends .of all the bearing bushings 15 terminate y thin recesses 6 formed 1n the cover plates, o that the end of the bearlng bushings are spaced from th outer walls of the cover plates. The shape f each recess 16 is clearly shown in Fig. 1 and,l as there shown, each recess surrounds the ends -of the bushings 15, extends from one bushing'to the other, and has a central portion which slopes downwardly toward the base of the pump. A port 17 connects the lower part of each recess 16 to the lower part of the gear chamber, as clearly shown in Flgs. 2 and 4.

The interior end walls of casing 10'are semi-circular, and the outer ends of the teeth slide on these semi-circular walls, as the gears are turned in the direction of the arrow shown in Fig. 4.v Chocolate enters the casing 10 centrally between the gears through an inlet pipe 18 threaded Into the bottom of casing 10. The chocolate 1s carried between the gear teeth, and the de-A scribed semi-circular endwalls upwardly and since no appreciable amount of chocolate can return centrally downward between the intermeshing gears, it is expelled upwardly through an outlet pipe 19 in the now well known manner. Y

The central upper and lower spaces between the intermeshing gears, contain chocolate at dilferent pressures, the pressure of the chocolate in space a bein higher than in space b. There is thus a orce, equal to the difference in fluid pressure in spaces a and b, which tends to move chocolate from the former to the latter. The sides of ears 1l closely lit between the covers 12 an 13, but there is a small amount of clearance therebetween, and some of the chocolate in space a is forced by Huid pressure to fill the clearance s aces and thus lubricate the ends or sides o v'the gears. The chocolate, between the sides of the gears and the cover members, is forced to travel from space a to space b and in so traveling some of the chocolate reaches the shafts 14 and passes from each side of the gears between the shafts'and their bushings 1'5 outwardly to the described recesses 416. The chocolate does not pass inwardly between the shafts andthe ars since the former tightly fit the latter. referably the bore of bushings 15 is provided with a plurality of grooves 20 (Fig. 6) to facilitate the passage of the cate the gears and shafts of the pump and furthermore in the construction shown the same portion is not likely to make this back eddy twice. v

It will now beapparent that` a pump of the type described is morev satisfactorily lubricated with chocolate when the latter is maintained in Huid condition.` T-o insure that the chocolate is kept in the fluid state, semi-circular jackets 21 and 22 are formed in the walls of casing 1, as clearlyshown in l`1g,`4. An inlet pipe 23 is cnnecteENo the Jacket 21 to admit a suitable heating medium (or cooling medium in hot weather), such as steam, hot water, cold water, and the like.' Jacket 22 is provided with an outlet p1pe 24 for the escape of the temperature controlling medium. The cover 13 is provided with a circuitous cored passage 25, one end of which is connected by a manifold 26 to the passage 2l and the other end by a manifold 27 to the passage 22. Thus, the temperature controlling` medium maypass from the passage 21 through manifold 26 to the passage 25 andthence through manifold 27 to the passage 22 and outlet 24. Thev other cover 12 may be similarly heated or cooled, if desired, but I have found that it is generally unnecessary so to do for enough radiation surface is rovided from the described passages to e ectually keep the choco' late ina fluid state and at a temperature at which its lubricating function is best accomplished.

A feature of particular importance is the lubrication of the bearings 15 and the sides of gears 11 by a circulation of a part of the .pumped material. As distingulshed from the lubrication of parts by using the lubricant over and over again, the describedV arrangement permits fresh lubricant to be continually fed to the moving parts. This is especially important, when as here the lubricant consists ofI chocolate or the like, for such substances soon lose their lubricating qualities if used repeatedly. The chocolate 1f so used, soonvburns and, when this happens, its effectiveness as a lubricating medium is destroyed, and injury tol the pump occurs through insuiiicient lubrica. 115 tion. The arrangement described' is furthermore characterized in that none of the chocolate is wasted. Although some of the chocolate pumped to space a iiows in a bypass path back to space b to lubricate the parts, this by-passed portion of the chocolate 1s subsequently returned by the gears to the space a and expelled. l

v A further feature of importance is the provisionof meansy to heat the chocolate as it passes throu h the pump, whereb the chocolate ma ie kept in fluid con ition.

As distinguis ed from ordinary lubricants,. chocolate is of the most lubricatin value when in the iuid state. Therefore, for successful lubrication of the pump by chocolate, the heating means is desirable and particularly when starting the pump, for, otherwise, the grooves 20 and the clearance spaces between gears and cover plates would be filled with hardened chocolate which, not only would have small lubricatin value, but would also prevent Huid choco ate drawn into the pump from passing in the desired circulatory lubricating paths. Furthermore, there is a certain range of temperaturc in which the chocolate is best adapted for lubrication, and, if the chocolate be maintained within this range by the heating or cooling means, its maximum lubricating value may be obtained.

I have now disclosed in detail the preferred form of my invention, but many other forms and arrangements will readily suggest themselves to those skilled in the art, having for their object the use of the invention in a specific form differing from the precise one disclosed. For example, the paths from thehigh to the low pressure side of the pump, and the type of rotating elements of the pump may be varied in numerous ways and still embody the invention. I, therefore, desire to have the scope of the invention determined by the following claim,

interpreted in the spirit of the disclosure of one exact forni rather than in the letter of the exact form disclosed.

What I claim is- A rotary pump, for pumping material of lubricating character, comprising a casing having an inlet and an outlet and being otherwise closed, a wall of said casing comprising an inner and an outer partition, spaced each from the other, the inner being provided with a journal bearing extending toward, but clear of, the outer, and open from end to end; said pump also comprising a rotary pumping element constructed to force material from the inlet to the outlet and place the material under pressure at the outlet, such element being provided with a shaft lying in said bearing with sufficient clearance to permit the passage of said material therealong, there being a connection between said clearance and the outlet side of said pump and there being a connection between the space between said partitions and the inlet side of said pump; whereby the material will be forced from the outlet side along said shaft, along thev entire length of said bearing, into said space, and to the inlet side of said pump; substantially as described.

ALONZO LINTON BAUSMAN. 

